Paul Epstein

Paul Epstein (1871-1939) was a German mathematician from Frankfurt, best known for his work in number theory and above all for the zeta functions that now carry his name. He studied at Strasbourg under Elwin Christoffel, took his doctorate there in 1895 with a thesis on hyperelliptic integrals, and remained a Privatdozent in the city until its return to France after the First World War sent him back to Frankfurt. In 1903 he introduced a class of Dirichlet series, depending on a quadratic form, that generalises the Riemann zeta function, and proved a functional equation, an analytic continuation and a Kronecker limit formula for them. These Epstein zeta functions matter in crystallography and in quantum field theory. He also taught the history of mathematics and wrote on Goethe and mathematics. A Jewish scholar, he gave up his teaching post before the Nuremberg laws took effect and took his own life in August 1939 after a summons from the Gestapo.